1. Field of the Invention
The present invention relates to a retracting mechanism for disengaging a magnetic head and a pinch roller from a magnetic tape and more particularly to a retracting mechanism so that the pinch roller is mechanically independent of the magnetic head.
2. Description of the Prior Art
U.S. Pat. No. 4,149,203, entitled Tape Recorder, issued to Minoru Kobayashi on Apr. 10, 1979, teaches a tape recorder which is provided with a controlling mechanism which includes a rockable control lever, a magnetic head support lever for supporting a magnetic head and a pinch roller support lever for supporting a pinch roller. The magnetic head support lever and the pinch roller support lever are mounted rockably and coaxially with each other. A first spring is stretched between the control lever and the head support lever to shift the magnetic head toward the tape accompanying the rocking motion of the control lever. A second spring is stretched between the control lever and the pinch roller support lever to shift the pinch roller toward the tape accompanying the rocking motion of the control lever. At least one of the first and second springs os charged with a returning force accompanying the magnetic head and the pinch roller shifting toward the tape whereby the controlling mechanism is capable of disjunctively controlling the magnetic head and the pinch roller away from the tape.
U.S. Pat. No. 4,188,647, entitled Cassette Type Tape Recorder, issued to Shinsaku Tanaka on Feb. 12, 1980, teaches a cassette tape recorder which includes a base plate and magnetic head carrying board which supports a magnetic head and a pinch roller and which has a cam pin inserted on one end portion. The cam pin is inserted into a cam hole in the base plate whereby the magnetic head and the pinch roller may be gradually rotated into place.
U.S. Pat. No. 3,832,735, entitled Cassette Loading and Unloading Apparatus, issued to Llyod K. Childress, Jr., George B. Flippen, Jr., and Louis M. McDaniels on Aug. 27, 1974, teaches a loading and unloading apparatus for a magnetic tape cassette which includes a retractable mechanism for inserting a read/write head and a pinch roller into the cassette. During the first extent of the travel of the door of the loading and unloading apparatus in opening the read/write head and the pinch roller are withdrawn from the cassette while the cassette is maintained in position.
U.S. Pat. No. 4,272,792, entitled Mode Changing System for a Cassette Tape Recorder, issued to Niro Nakamichi, Kozo Kobayashi and Hideo Kawachi, teaches a mode changing system for a cassette tape recorder wherein the operating members, such as the head plate and a pinch roller are moved in accordance with the operating modes of the cassette tape recorder.
U.S. Pat. No. 4,303,954, entitled Control Device for a Tape Recorder, issued to Fritz Wisser on Sept. 1, 1981, teaches a control device which includes a mount for a pinch roller which is movably mounted on a base plate in a direction of movement between an operating position and a rest position.
U.S. Pat. No. 4,196,874, entitled Drive Apparatus for a Tape Recorder, issued to Kenji Ohara on Apr. 8, 1980, teaches a drive apparatus for a tape recorder which includes a pair of spaced apart selectively driven wheels, a motor and a drive wheel is located between parallel planes and is selectively rotated in first and second opposed rotary directions by means of the motor. The apparatus also includes an idler wheel engaging the drive wheel so as to be rotated thereby and a pivotally mounted support arm rotatably carrying the idler wheel and being swingable between a first position where the idler wheels bears against one of the driven wheels for driving the latter from the drive wheel and a second position where the idler wheel bears against the other of the driven wheels for driving the other driven wheel fron the drive wheel. The drive apparatus further includes a non-contacting magnetic means including at least one coupling member which is spaced apart from the idler wheel for magnetically coupling the idler wheel with the support arm so as to yieldably resist relative motion thereof and thereby cause swinging of the support arm to the first and second positions in response to the rotation of the drive wheel in the first and second rotary directions, respectively.
U.S. Pat. No. 4,196,875, entitled Magnetic Tape Recording and/or Reproducing Apparatus, issued to Masaichiro Tatckawa, Toshiharu Sasaki and Yoshihito Urata, teaches a magnetic tape recording and/or reproducing apparatus which includes in combination a capstan driving motor, a pair of tape winding means, a reel driving motor, a pinch roller and at least one idel wheel.
U.S. Pat. No. 4,253,128, entitled Dual Spring Loaded Operating Mechanism for a Tape Recorder, issued to Shoichi Saito and Hirpyuki Yamada on Feb. 24, 1981, teaches a pinch roller supporting fitting which operates in conjunction with a spring which biases the pinch roller against a capstan drive shaft.
U.S. Pat. No. 4,232,349, entitled Mode Switching Mechanism for a Cassette Tape Recorder, issued to Minoru Kobayashi on Nov. 4, 1980, teaches a support lever for a magnetic head and a pinch roller.
In each of the above retracting mechanisms for the magnetic head and the pinch roller of the tape recorder of the prior art the pinch roller is mechanically coupled to magnetic head. When both the pinch roller and the magnetic head engage the magnetic tape, any eccentricity of the pinch roller, such as a flat spot, cause a movement of the pinch roller support lever. This movement is transmitted to the magnetic head through the retracting mechanism and causes a distortion to the recording and/or playing signals of the tape recorder. In none of the retracting mechanisms is the pinch roller mechanically independent of the magnetic head, when the pinch roller and the magnetic head engage the magnetic tape, and retractably coupled, when the magnetic head and the pinch roller disengage the magnetic tape.